Field of the Invention
The present invention relates to a pouch type case including an electrolyte injection part corrugated in a zigzag shape, a battery cell including the pouch type case, and a method of manufacturing a battery cell.
Description of the Related Art
Batteries generate electric energy through a chemical or physical reaction. Such chemical batteries are classified into primary batteries and secondary batteries. In particular, the primary batteries are not rechargeable, examples of which include manganese batteries, alkaline batteries, and mercury batteries, and the secondary batteries are rechargeable, examples of which include rechargeable batteries and lead storage batteries.
As portable electronic devices, such as cellular phones, PDAs, smart phones, and notebook computers come into wide use, technical developments of secondary batteries, which can be used for a long time on a single charge and have long service life, are needed.
Such a secondary battery is provided in a battery cell form in which a plurality of cells, that is, a plurality unit batteries are connected to each other according to charging/discharging efficiency or current capacity. Lithium secondary batteries having advantages such as high energy density, lightness, high voltage, non-pollution, high power, quick charge, and long service life are currently popular.
The above described battery cell form is disclosed in detail in Korean Patent Publication No. 10-2012-0061354.
That is, referring to FIG. 1, a pouch type battery cell 10 in the related art includes a pouch type case 20 and an electrode assembly 30.
The pouch type case 20 has a structure in which upper and lower cases 21 and 22 are brought into tight contact with and are coupled to each other.
The electrode assembly 30 has a structure in which unit cells A are repeatedly stacked. The unit cells A include a cathode plate, an anode plate, and a separator disposed between the cathode plate and the anode plate. The cathode plate is provided with a cathode tab, and the anode plate is provided with an anode tab.
The pouch type battery cell 10 configured as described above is completed by putting the electrode assembly 30 in the pouch type case 20, injecting electrolyte therein, and then, performing a sealing process and a post-treatment process.
Referring to FIG. 2, the pouch type case 20 is provided with an injection part 23 for facilitating the injecting of the electrolyte, and the injection part 23 is elongated from a non-sealing surface of the pouch type case 20.
After the electrolyte is injected into the pouch type case 20, the pouch type battery cell 10 is put in a vacuum chamber (not shown) to perform an impregnating process. At this point, the pouch type case 20 is compressed by inner pressure of the vacuum chamber, and the electrolyte injected in the pouch type case 20 is easily discharged to the outside through the injection part 23.
Moreover, since the injection part 23 of the pouch type case 20 is vertically elongated, the injection part 23 is easily compressed by the inner pressure of the vacuum chamber, and the electrolyte is easily discharged to the outside.